Microsoft is adding 38 additional file extensions to its list of file extensions that are blocked from being downloaded as attachments in Outlook on the Web. The list of blocked file extensions currently has 104 entries, including. extensions used by Python scripting language, Java programming language and various applications. Microsoft says most organizations will not be affected by the change, but if your users are sending and receiving affected attachments, they will report that they are no longer able to download them. Google, the largest email provider, also maintains a list of. files that the company considers harmful to Gmail users.
Source: https://thehackernews.com/2019/09/email-attachment-malware.html